body {
    max-width: 540px;
    min-width: 320px;
    margin: 0 auto;
    font: normal 14px/1.5 Tahoma, "Lucida Grande", Verdana, "Micrsoft Yahei", STXihei, hei;
    color: #000;
    background-color: #f2f2f2;
    overflow-x: hidden;
    -webkit-tap-highlight-color: transparent;
}

ul {
    margin: 0;
    padding: 0;
    list-style: none;
}

a {
    text-decoration: none;
    color: #222;
}

div {
    box-sizing: border-box;
}